Integrated circuits such as, for example, integrated memory circuits, are used in different data configurations or organization forms. The organization forms differ, in particular, in the number of data lines used, which are connected to data connection pads, i.e., I/O pads. With the selection of one of the organization forms that can be set, it is possible to set a system bus width predetermined by the surroundings. The circuit design of the module to be configured is uniform. The data connection pads provide external communication, in particular, for the exchange of data between the integrated circuit and a system controller, for example. There are, for example, ×4, ×8 and ×16 organization forms that use 4, 8 or 16 data lines per circuit or module for the data exchange.
If, in terms of its basic conception, an integrated circuit can be used in all ×4, ×8 and ×16 organization forms and can accordingly be configured in the data width of a data bus of the circuit, it becomes necessary to set the relevant organization form before the commissioning of the integrated circuit. A plurality of connection pads are generally provided for this purpose. The connection pads can be connected externally in order to define a respective organization form.
In order to set the three aforementioned organization forms of an integrated circuit, two connection pads, for example, which are connected in three different ways, are provided. For this purpose, the connection pads are either connected ground, for example, or left open. For example, for setting the respective organization forms, different states are generated. In the case where a first connection pad is connected to ground, in the case where a second connection pad is connected up to ground and in the case where both connection pads are left open. Each of the states is significant for an organization form.
Such a configuration of an integrated circuit defines that organization form of the organization forms in which the integrated circuit is operated in the application. It is thus necessary for the manufacturer of such an integrated circuit to already define, in the course of manufacture, that organization form of the organization forms in which the circuit is configured. Accordingly, the logistics for the individual respective circuit configurations have to be coordinated with the precise requirement of the individual configurations both on the part of the manufacturer and on the part of the customer. In particular, it is necessary to coordinate the manufacturing, storage and supply capacities for the individual configurations and also the ordering process with the precise requirement of the respective circuit configuration. Furthermore, it is necessary, when building up stocks for the individual circuit configurations, to make a relatively precise prediction of the future sales of the respective circuit configuration in order to be able to keep the stocks relatively low.
A DRAM memory in which refresh intervals and the organization form for data can be set differently is known. A memory register, for example, an MRS (Mode Register Set) register, is programmed externally. The MRS register generates decoded control signals that are used to drive a selection circuit for selection of the refresh intervals and a selection circuit for selection of the data organization. Depending on the programmed state of the MRS register, it is thus possible, by the selection circuits, to program different refresh intervals and different data organization forms for the DRAM memory.
Also a memory system having a variable setting of the organization form is known. The memory system comprises two memory segments, of which each segment has a word length of m/2 and a bit length of n/2, where m specifies the maximum word length and n specifies the maximum bit length. The memory system can be operated in a first organization form with a word length m and a bit length n/2 and in a second organization form with a word length m/2 and the bit length n. For selection of one of the two organization forms, external connections of the memory system are driven with different potentials or the external connections are short-circuited among one another in different ways.
A circuit for setting one of a plurality of organization forms of an integrated circuit which makes it possible to achieve a gain in flexibility with regard to the usability of the integrated circuit in the different organization forms is desirable.